Better hope she starts a band. The Riot Grrl movement was 20 years ago. This article catches up on some of the big names of the time, and discusses what's become academic interest in the intersection of feminism, music and social protest.
What I do remember about Riot Grrl was that along with tweaking people with the kinderwhore look, the music and scene was focused on feminism, taking women seriously, and talking about things like date rape and sexual harassment and gender inequity. Which leads me to this piece by Julie Klausner, her valentine to maturity and question of why women like to behave like nonthreatening children. She thinks it's so we don't threaten the manboys, which is a viable theory. I think that adulthood and a willingness to embrace it depends on a lit of personal issues, but damn it if I don't get awed when I see women being portrayed as serious adults.
Speaking of women who walk the line between being girly and being adult, check out this excerpt of Mindy Kaling's book. It looks really good.